This invention generally relates to image-forming production systems. More particularly, this invention relates to improving the operation of a registration system in the image-forming production system.
Image-forming production systems, such as high volume electrographic printers and copiers, are used to transfer images onto a plurality of sheets of paper or other medium. In a typical image-forming job, the image-forming production system transfers or prints one or more images onto one or more sheets. When multiple images are transferred, the image-forming process usually transfers the images to arrange the output sheets according to the image-forming job. The output sheet sequence typically corresponds to the image input sequence into the image-forming production system. This ordered input and corresponding output avoids the need to reassemble or otherwise compile the sheets.
Many image-forming production systems have a marking engine, an inserter, and a finisher device. The marking engine transfers or prints images onto the sheets. If required by the image-forming job, the inserter inserts a tab, preprinted sheet, a blank sheet or other stock sheet into the sheet output from the marking engine. The finisher device collects the output sheets to complete the image-forming job or prepare it for subsequent processing operations.
The marking engine usually includes image-forming equipment, a sheet feeder and a registration system. The sheet feeder provides the selected paper or other medium to the image-forming production system for transferring or printing an image at an imaging and registration system in the marking engine. The imaging system includes an imaging loop. The registration system aligns the paper to a photoconductor in the correct position, orientation and at the correct time. The selected paper may arrive at the registration system at any time from various parts of the image-forming production system. The impreciseness or variability at which the paper arrives at the registration system may impede the registration system from effectively aligning and orientating the paper before it is sent through the registration system. Moreover, in an electrographic marking engine, it is desirable to minimize the speed at which an image is processed and fused for a given throughput rate. This is accomplished by positioning the sheets relatively close to each other in the direction of feed. On the other hand, paper feeders generally desire a higher transport speed. This is because high-speed feeders use vacuum feeding due to its superior reliability and performance compared to other types of feeders. For maximum performance these vacuum type feeding systems require a significant time between sheets in order to safely acquire the sheet with vacuum prior to feeding. This is accomplished by transporting the sheet at higher speed while feeding, leaving more time between feeds for acquiring the next sheet. This speed is sometimes higher than that at which the registration system can reliably accommodate. Thus there is a conflict between the desired relatively lower speed of the imaging system and the desired higher speed for the sheet feeders.
Accordingly, there is a need for an image-forming production system that is able to transfer sheets of paper to a registration system, where the transfer occurs at a time that is coordinated with the timing of the registration system.
The present invention is an apparatus and method that may be used in an image-forming production system that includes a marking engine. Such systems may also include a paper supply module, an inserter and a finisher device. The image-production system includes a marking engine that receives at least one sheet and preferably a plurality of sheets onto which an image is transferred. A sheet feeder that feeds the sheet to the marking engine at a first speed. The marking engine includes an imaging system that transfers the image onto the sheet. A registration system is upstream of the imaging system, which aligns the sheet to the imaging system and moves the sheet through the imaging system at a second speed. The marking engine has an output downstream of the imaging system. A speed adjust system is disposed upstream of the registration system. The speed adjust system is connected to receive the sheet from the sheet feeder at the first speed and output the sheet to the registration system at the second speed. Preferably the speed adjust system also determines the correct time to feed the at least one sheet to the registration system.
In a preferred embodiment, the marking engine includes a marking engine controller and a speed adjust system. The speed adjust system includes a speed adjust system controller. The marking engine transmits a synch pulse signal to the speed adjust system controller. The speed adjust system transmits a signal to the speed adjust system sensor upon the arrival of the sheet. The speed adjust system controller compares the measured arrival time with the synch pulse signal to adjust a speed of the sheet before the sheet is transferred to the registration system.
Other systems, methods, features, and advantages of the invention will be or will become apparent to one skilled in the art upon examination of the following figures and detailed description. All such additional systems, methods, features, and advantages are intended to be included within this description, within the scope of the invention, and protected by the accompanying claims.